It is worth pointing out that there are some nice diminished chords in open D. The two easiest shapes seem to be:
These go nicely in something like from D to A7 (and back to D):
with the D alternating on the 6th string, or the 4th string, or the 1st string.
I stole this from a recent article in Acoustic Guitar magazine by Mike Dowling.
yours, Peter T.